Well that’s not with every broker, there are many brokers that are legitimate and offers tight spreads as well, here are some good broker with low spreads:
https://www.elitetrader.com/et/threads/list-of-best-regulated-brokers.362682/
I agree with you, demo trading helps in making aware of the market as well as of the platform which one will be going to use. When I started trading, I practised my strategies on fxview’s demo account for months before going live with them.
Well, I think it’s better to open a demo account first to check the reliability of a broker, I have come across this thread, it consists of pretty good list of brokers, you can have a look:
https://elitetrader.com/et/threads/list-of-best-regulated-brokers.362682/
You can’t avoid broker’s fees but for a low cost trading experience you can go with brokers that have tight spreads and commissions such as fxview, and tickmill.
I think that the trading psychology depends on the trader’s mindset, there is no as such course according to me, you need to develop your mind in such a way that it doesn’t let you go off the track.